Guilds of Ravnica: Thousand-Year Storm

Whenever you cast an instant or sorcery spell, copy it for each other instant and sorcery spell you've cast before it this turn. You may choose new targets for the copies.

Pro Tip!
Ral Zarek's latest science project will help you generate tons of value. With plenty of good can-trips in Standard, you can cast a slew of card-draw spells on your turn, then win by copying burn spells!